El Niño s Role in Polynesian Navigation

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1 El Niño s Role in Polynesian Navigation Based on an In-Depth Study of the Years by Vincent H. Malmström Professor Emeritus of Geography Dartmouth College

2 Heyerdahl s Theory of Pacific Settlement Because the dominant winds and ocean currents in the tropical Pacific are from east to west, Thor Heyerdahl believed it would have been impossible for the Polynesians to have settled the region from the west, i.e., Asia Instead, he argued that the most likely way the islands were populated was from the east, namely from the Americas

3 Most Archaeologists Strongly Disagreed They noted that the language of the Polynesians, as well as their racial affinities and basic foodstuffs, all derive from Asian origins Only one basic crop -- the sweet potato -- is of American origin, as is its native name, kumara

4 From Samoa to the Marquesas After the Polynesians reached Samoa about 1500 BC, we don t hear from them again until about 100 AD When we do, they show up in the easternmost island group in the entire Pacific -- the Marquesas Interestingly, the author s computer simulation of early sailing in the Pacific, which he first tested in 1985, replicated this finding perfectly

5 The Rising Point of Aldebaran Was a Safe Guide to the Marquesas

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8 Another Computer Finding What the computer simulation also revealed was that if, by chance, the Marquesas were bypassed by the Polynesians, their next landfalls would likely be either the Galápagos Islands or the coast of southern Ecuador Coming ashore at the latter point would have brought them in contact with the Cañarí Indians, who not only grew sweet potatoes but also called them kumara!

9 The Author Visits Ecuador in 1982 My second research trip to Ecuador in 1982 happened to coincide with an El Niño year, when heavy rains moved in from the Pacific to the west They accompany a back-wash of the Equatorial Counter-Current from eastern Asia, and recur every six to seven years

10 New Odds for Reaching America This means that, if the Polynesians had been out sailing in an El Niño year -- which occurs about 16% of the time -- they would have had tail-winds right into the coast of southern Ecuador -- a situation of which Heyerdahl was obviously not aware

11 The Earliest Clues Show Up to the West When an El Niño back-wash occurs, the earliest places to feel its effects will be out to the west of Ecuador, in the Galápagos Islands To test this notion, the author investigated the latest decade of climatic data from the areas most likely to be affected; the place that turned out to always bear the brunt of these events is the Ecuadorean seaport of Guayaquil

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33 The Coastal Effects of El Niño When the Equatorial Counter-Current reaches South America, part of it branches northward along the coast of Ecuador and Colombia where it joins a flow of warm water and part of it branches southward along the coast of Peru where it floats on top of a very cold current

34 The Impact on Peru is Serious The warm southward flowing branch kills off the plankton in the cold water, a source of food for large schools of fish which are also the source of food for sea-birds As this ecological catastrophe unfolds, fish catches often drop by 2/3 during an El Niño event, seriously affecting the local economy

35 The Following Slides Trace El Niño Toward the South The coastal rain falls off sharply as the warm water is chilled by the cold current below From its peak in the Guayaquil area, it declines to almost nothing within a couple hundred miles The Atacama desert extends along the entire coast of Peru and the northern third of Chile, a barren strip of sand and rock punctuated by about 40 small river valleys

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41 The Warm Northward Branch Brings Rains Along the Ecuadorean Coast Porto Viejo and Esmeraldas illustrate the effect along this stretch of coast The native vegetation here changes from desert to scrub to full-fledged tropical rain forest in just a matter of a few miles

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46 Ecuador s Unique Geographic Location

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49 During El Niño Events, the Rain Belt Shifts Eastward

50 During La Niña Events, the Rain Belt Shifts Westward

51 White areas = Warm Water Purple areas = Cold Water

52 Cyclical Variations in Pacific Water Temperatures

53 Temperature Monitoring System

54 A Case Study of the 1982 El Niño The morning that my student assistant and I were leaving Quito, the capital of Ecuador, for Guayaquil, its main port on the Pacific, the local newspapers told of three little boys, playng in the street, having been washed away the night before by a torrent of rainwater -- never to be found again!

55 Our Rail Journey to the Coast Our train consisted of a Blue Bird school bus fitted with railway wheels and holding a total of 44 passengers As we began our climb out of Quito, the little stream alongside the track was about 6-8 feet wide By the time we reached the pass, it was a roaring river about 300 feet wide

56 The Moment of Decision The driver had to stop where the river crossed the rail-line, because it wasn t obvious if the tracks were still there As we waited for the water to drop, a dead bull and several large logs floated by Although the tracks were clogged with debris, the driver gunned it and we made it across, to the applause of the passengers

57 The Train or Auto-Ferro

58 The Challenge

59 Although we don t know the real number of casualties of the 1982 El Niño, that of 1998 is reckoned to have been responsible for over 2000 deaths -- most of them well beyond the borders of Ecuador and Peru, where it had its most immediate impact The End